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Fast, non-monte-carlo estimation of transient performance variation due to device mismatch
This paper describes an efficient way of simulating the effects of device random mismatch on circuit transient characteristics, such as variations in delay or in frequency. The proposed method models DC random offsets as equivalent AC pseudo-noises and leverages the fast, linear periodically time-varying (LPTV) noise analysis available from RF circuit simulators. Therefore, the method can be considered as an extension to DC match analysis and offers a large speed-up compared to the traditional Monte-Carlo analysis. Although the assumed linear perturbation model is valid only for small variations, it enables easy ways to estimate correlations among variations and identify the most sensitive design parameters to mismatch, all at no additional simulation cost. Three benchmarks measuring the variations in the input offset voltage of a clocked comparator, the delay of a logic path, and the frequency of an oscillator demonstrate the speed improvement of about 100-1000x compared to a 1000-point Monte-Carlo method
Cyclostationary noise modeling of radio frequency devices
We present a review of the current status of research in the modeling and simulation of cyclostationary (nonlinear) noise properties of semiconductor active devices operated in forced large-signal conditions, a typical operating regime for high-frequency applications. We discuss both the case of physics-based device simulations, where numerical burden is the most important issue, and the derivation of compact cyclostationary noise models. In the latter case, both phenomenological amplitude modulation approaches and the derivation of consistent analytical device descriptions are discussed. We show examples of both physics-based simulations of the noise properties of a realistic high-electron mobility transistor resistive mixer and show for the first time the application of a novel, fully analytical cyclostationary noise bipolar transistor model
Compact conversion and cyclostationary noise modelling of pn junction diodes in low-injection - Part II: Discussion
Starting from the compact conversion and cyclostationary pn diode noise model presented in the companion paper, we present an extensive validation based on comparisons with physics-based numerical simulations. Furthermore, we discuss the validity of two widely exploited system-oriented cyclostationary noise modeling approaches, based on the modulation of small-signal stationary noise spectra. We demonstrate that care must be exerted in the choice of the modulation scheme, unless the intrinsic diode noise is purely white, in which case a simple modulated shot noise approach can provide, with proper inclusion of parasitics, satisfactorily accurate results
Memristor: Modeling, Simulation and Usage in Neuromorphic Computation
Memristor, the fourth passive circuit element, has attracted increased attention from various areas since the first real device was discovered in 2008. Its distinctive characteristic to record the historic profile of the voltage/current through itself creates great potential in future circuit design. Inspired by its high Scalability, ultra low power consumption and similar functionality to biology synapse, using memristor to build high density, high power efficiency neuromorphic circuits becomes one of most promising and also challenging applications. The challenges can be concluded into three levels: device level, circuit level and application level.
At device level, we studied different memristor models and process variations, then we carried out three independent variation models to describe the variation and stochastic behavior of TiO2 memristors. These models can also extend to other memristor models. Meanwhile, these models are also compact enough for large-scale circuit simulation.
At circuit level, inspired by the large-scale and unique requirement of memristor-based neuromorphic circuits, we designed a circuit simulator for efficient memristor cross-point array simulations. Out simulator is 4~5 orders of magnitude faster than tradition SPICE simulators. Both linear and nonlinear memristor cross-point arrays are studied for level-based and spike-based neuromorphic circuits, respectively.
At application level, we first designed a few compact memristor-based neuromorphic components, including ``Macro cell'' for efficient and high definition weight storage, memristor-based stochastic neuron and memristor-based spatio temporal synapse. We then studied three typical neural network models and their hardware realization on memristor-based neuromorphic circuits: Brain-State-in-a-Box (BSB) model stands for level-based neural network, and STDP/ReSuMe models stand for spiking neural network for temporal learning. Our result demonstrates the high resilience to variation of memristor-based circuits and ultra-low power consumption.
In this thesis, we have proposed a complete and detailed analysis for memristor-based neuromorphic circuit design from the device level to the application level. In each level, both theoretical analysis and experimental data versification are applied to ensure the completeness and accuracy of the work
Real-Time Fault Detection and Diagnosis System for Analog and Mixed-Signal Circuits of Acousto-Magnetic EAS Devices
© 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The paper discusses fault diagnosis of the electronic circuit board, part of acousto-magnetic electronic article surveillance detection devices. The aim is that the end-user can run the fault diagnosis in real time using a portable FPGA-based platform so as to gain insight into the failures that have occurred.Peer reviewe
Stability of attitude control systems acted upon by random perturbations
Mathematical models on stability of attitude control systems acted upon by random perturbation processe
Worst-Case Analysis of Electrical and Electronic Equipment via Affine Arithmetic
In the design and fabrication process of electronic equipment, there are many unkown parameters which significantly affect the product performance. Some uncertainties are due to manufacturing process fluctuations, while others due to the environment such as operating temperature, voltage, and various ambient aging stressors. It is desirable to consider these uncertainties to ensure product performance, improve yield, and reduce design cost. Since direct electromagnetic compatibility measurements impact on both cost and time-to-market, there has been a growing demand for the availability of tools enabling the simulation of electrical and electronic equipment with the inclusion of the effects of system uncertainties.
In this framework, the assessment of device response is no longer regarded as deterministic but as a random process. It is traditionally analyzed using the Monte Carlo or other sampling-based methods. The drawback of the above methods is large number of required samples to converge, which are time-consuming for practical applications. As an alternative, the inherent worst-case approaches such as interval analysis directly provide an estimation of the true bounds of the responses. However, such approaches might provide unnecessarily strict margins, which are very unlikely to occur. A recent technique, affine arithmetic, advances the interval based methods by means of handling correlated intervals. However, it still leads to over-conservatism due to the inability of considering probability information.
The objective of this thesis is to improve the accuracy of the affine arithmetic and broaden its application in frequency-domain analysis. We first extend the existing literature results to the efficient time-domain analysis of lumped circuits considering the uncertainties. Then we provide an extension of the basic affine arithmetic to the frequency-domain simulation of circuits. Classical tools for circuit analysis are used within a modified affine framework accounting for complex algebra and uncertainty interval partitioning for the accurate and efficient computation of the worst case bounds of the responses of both lumped and distributed circuits.
The performance of the proposed approach is investigated through extensive simulations in several case studies. The simulation results are compared with the Monte Carlo method in terms of both simulation time and accuracy
Anålisis y diseño de multiplicadores y mezcladores mediante el Método de Monte CArlo en la banda de THZ
[ES]La regiĂłn del espectro electromagnĂ©tico comprendida entre 100 GHz y 10 THz alberga una gran variedad de aplicaciones en campos tan dispares como la radioastronomĂa, espectroscopĂa molecular, medicina, seguridad, radar, etc. Los principales inconvenientes en el desarrollo de estas aplicaciones son los altos costes de producciĂłn de los sistemas trabajando a estas frecuencias, su costoso mantenimiento, gran volumen y baja fiabilidad. Entre las diferentes tecnologĂas a frecuencias de THz, la tecnologĂa de los diodos Schottky juega un importante papel debido a su madurez y a la sencillez de estos dispositivos. AdemĂĄs, los diodos Schottky pueden operar tanto a temperatura ambiente como a temperaturas criogĂ©nicas, con altas eficiencias cuando se usan como multiplicadores y con moderadas temperaturas de ruido en mezcladores. El principal objetivo de esta tesis doctoral es analizar los fenĂłmenos fĂsicos responsables de las caracterĂsticas elĂ©ctricas y del ruido en los diodos Schottky, asĂ como analizar y diseñar circuitos multiplicadores y mezcladores en bandas milimĂ©tricas y submilimĂ©tricas.
La primera parte de la tesis presenta un anĂĄlisis de los fenĂłmenos fĂsicos que limitan el comportamiento de los diodos Schottky de GaAs y GaN y de las caracterĂsticas del espectro de ruido de estos dispositivos. Para llevar a cabo este anĂĄlisis, un modelo del diodo basado en la tĂ©cnica de Monte Carlo se ha considerado como referencia debido a la elevada precisiĂłn y fiabilidad de este modelo. AdemĂĄs, el modelo de Monte Carlo permite calcular directamente el espectro de ruido de los diodos sin necesidad de utilizar ningĂșn modelo analĂtico o empĂrico. Se han analizado fenĂłmenos fĂsicos como saturaciĂłn de la velocidad, inercia de los portadores, dependencia de la movilidad electrĂłnica con la longitud de la epicapa, resonancias del plasma y efectos no locales y no estacionarios. TambiĂ©n se ha presentado un completo anĂĄlisis del espectro de ruido para diodos Schottky de GaAs y GaN operando tanto en condiciones estĂĄticas como variables con el tiempo. Los resultados obtenidos en esta parte de la tesis contribuyen a mejorar la comprensiĂłn de la respuesta elĂ©ctrica y del ruido de los diodos Schottky en condiciones de altas frecuencias y/o altos campos elĂ©ctricos. TambiĂ©n, estos resultados han ayudado a determinar las limitaciones de modelos numĂ©ricos y analĂticos usados en el anĂĄlisis de la respuesta elĂ©ctrica y del ruido electrĂłnico en los diodos Schottky.
La segunda parte de la tesis estĂĄ dedicada al anĂĄlisis de multiplicadores y mezcladores mediante una herramienta de simulaciĂłn de circuitos basada en la tĂ©cnica de balance armĂłnico. Diferentes modelos basados en circuitos equivalentes del dispositivo, en las ecuaciones de arrastre-difusiĂłn y en la tĂ©cnica de Monte Carlo se han considerado en este anĂĄlisis. El modelo de Monte Carlo acoplado a la tĂ©cnica de balance armĂłnico se ha usado como referencia para evaluar las limitaciones y el rango de validez de modelos basados en circuitos equivalentes y en las ecuaciones de arrastre-difusiĂłn para el diseño de circuitos multiplicadores y mezcladores. Una notable caracterĂstica de esta herramienta de simulaciĂłn es que permite diseñar circuitos Schottky teniendo en cuenta tanto la respuesta elĂ©ctrica como el ruido generado en los dispositivos. Los resultados de las simulaciones presentados en esta parte de la tesis, tanto para multiplicadores como mezcladores, se han comparado con resultados experimentales publicados en la literatura. El simulador que integra el modelo de Monte Carlo con la tĂ©cnica de balance armĂłnico permite analizar y diseñar circuitos a frecuencias superiores a 1 THz.[EN]The terahertz region of the electromagnetic spectrum (100 GHz-10 THz) presents a wide range of
applications such as radio-astronomy, molecular spectroscopy, medicine, security and radar, among
others. The main obstacles for the development of these applications are the high production cost of
the systems working at these frequencies, high maintenance, high volume and low reliability. Among
the different THz technologies, Schottky technology plays an important rule due to its maturity
and the inherent simplicity of these devices. Besides, Schottky diodes can operate at both room
and cryogenic temperatures, with high efficiency in multipliers and moderate noise temperature in
mixers. This PhD. thesis is mainly concerned with the analysis of the physical processes responsible
for the characteristics of the electrical response and noise of Schottky diodes, as well as the analysis
and design of frequency multipliers and mixers at millimeter and submillimeter wavelengths.
The first part of the thesis deals with the analysis of the physical phenomena limiting the electrical
performance of GaAs and GaN Schottky diodes and their noise performance. To carry out this
analysis, a Monte Carlo model of the diode has been used as a reference due to the high accuracy
and reliability of this diode model at millimeter and submillimter wavelengths. Besides, the Monte
Carlo model provides a direct description of the noise spectra of the devices without the necessity
of any additional analytical or empirical model. Physical phenomena like velocity saturation, carrier
inertia, dependence of the electron mobility on the epilayer length, plasma resonance and nonlocal
effects in time and space have been analysed. Also, a complete analysis of the current noise spectra
of GaAs and GaN Schottky diodes operating under static and time varying conditions is presented
in this part of the thesis. The obtained results provide a better understanding of the electrical and the
noise responses of Schottky diodes under high frequency and/or high electric field conditions. Also
these results have helped to determine the limitations of numerical and analytical models used in the
analysis of the electrical and the noise responses of these devices.
The second part of the thesis is devoted to the analysis of frequency multipliers and mixers by
means of an in-house circuit simulation tool based on the harmonic balance technique. Different
lumped equivalent circuits, drift-diffusion and Monte Carlo models have been considered in this
analysis. The Monte Carlo model coupled to the harmonic balance technique has been used as a
reference to evaluate the limitations and range of validity of lumped equivalent circuit and driftdiffusion
models for the design of frequency multipliers and mixers. A remarkable feature of this
reference simulation tool is that it enables the design of Schottky circuits from both electrical and
noise considerations. The simulation results presented in this part of the thesis for both multipliers
and mixers have been compared with measured results available in the literature. In addition, the
Monte Carlo simulation tool allows the analysis and design of circuits above 1 THz
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